Hydraulic cushion for metal presses



June 25, 1929. F. J. RODE a' HYDRAULIC CUSHION FOR METAL PRESSES FiledApril '7, 1928 3 Sheets-Sheet June 25, 1925. I F, J, RODE 1,718,435

HYDRAULIC CUSHION FOR METAL PRESSES Filed April 7, 1928 3 Sheets-SheetJune 25, 1929. F, J, RODE 1,718,435

HYDRAULIC CUSHION FOR METAL PRESSES Filed April '7, 1928 3 Sheets-Sheet3 Patented June 25, 1929.

UNITED STATESy PATENT foFFlcE.

FRIEDRICH J'. RODE, OF CHICAGO, ILLINOIS, ASSIGNOR TO MARQETTE TOOL &MIG.

' CO., OF CHICAGO, ILLINOIS, A CORPORATION` 0F ILLINOIS.

HYDRAULIC CUSHION FOR METAL PRESSES.

i Application med april 7,

In hydraulic cushioning devicesy for presses of the character in whichthe metal is shaped by means of co-operating dies, one of which dies isreciprocable toward and away from the other, the wor'k being clamped orheld by means of a blank or Work holding element that co-operates withthe reciprocable die member, and the blank or work holder ele-v mentbeing resisted in its movement in one direction by the said cushion, ithas been found that when the piston in the cushioning device starts tomove 'against the stress or resistance of the liquid, and especiallywhen said liquid is non-compressible, there is a severe shock impartedto the machinery before the liquid starts to move under the stress oraction of the piston. This shock is undesirable and detrimental as itstrains the parts of the press, oftentimes resulting in considerableinjury.

It is oneof'the objects ofthe present invention to overcome thesedifficulties and objections and to provide in a cushion of thischaractery improved means for automatically eliminating or relieving theparts of the press and machine `from such shocks or strams. f v

To the attainment of these ends and the accomplishment of othernew anduseful objects as Will ap ear, the invention consists in the features onovelty inl substantially the construction, combination and arrangementof the several 'parts'hereinaftermore fully described` and claimed randshown in the accompanying drawings illustrating this invention, andV in"which Y Figure 1 is a view partly in side elevation, partly infsection, with arts broken away and .with parts omitted o asheet metalpress having a cushioning means constructed in accordance with theuprinciples of this in-v vention applied thereto, tion which the partswill lassume when the ram or movable die-member issubstantially` at thelimit of its upward movement.

Figure 2 is a view in side elevation of Figure l with parts omitted,parts broken away and `parts in section.`

Figure 3 is an enlarged view paru-y in @1evation,

partly in section `and partly broken away and with parts omitted, showinthe position of the parte when the ram or p ungshowing the posiymeral30.v

1928. Serial N'o. 268,325.

er is at the limit of its lowermost movement.

Referring more particularly to the drawings the numeral 10 designatesgenerally the support of the press upon which the bed plate 11 rests,uprights 12 being provided and along whichl uprights the ram or plunger13 carrying the movable die member 14 is reciprocable by means of acrank shaft 15 journaled in the uprights, and which shaft is rot-ated ina manner usual in presses of this character.

Mounted upon thebed plate 11 is a die 16 with which the reciprocatmg dieco-operates. Encompassing the die 16 is a blank or work holding member17, the latter being supported by means of pins 18 which pass looselythrough the bed plate 11 and have contact with and are supported bymeans of apressure late or pad 19, all as usual in presses of t ischaracter.

As shown in Figure 2 of the drawing, the pressure pad 19 constitutes anextension of a pad or plate 20, through the medium of supporting pins21.

Arranged beneath the press and mounted upon a suitable support 22, whichlatter may be held in position by means of hanger memvation and isprovided with a predetermined A supply of liquid through a suitable fillopenine28. ading from the tank is a pipe 29 which has communication withthe bottom of the cylinder 24 beneath the piston 25.

Arranged in the pipe 29 and at an suitable point is a valve containing eement designated generally by .the reference nu- This element has apassage 3L therethrough, which when open will permit the liquid to flowvfrom the tank 27 through the upper portion of the pipe 29 and into thelower portion of the pipe 29 to' be delivered to the cylinder. 1

This passage 31 is provided with a valve seat 32 with which a valve 33vco-operates for opening and closing the passage to permit or interruptthe flow of liquid therethrough. I

-The valve 33 is adapted to be controlled in any suitable manner so asto yieldingly hold the same upon the seat 32 and to that end there maybe provided a cylinder 34 within which is a piston 35 that is connectedtothe valve stem 36, the cylinder being held .in position in anysuitable manner so that the valve stem 36 will pass through' a suitableguide 37.

Communicating with the top of the .cyl-

i inder 34 and on the upper `side of the piston is a pipe 38 whichdelivers iluid, such as air to the cylinder from any suitable sourcethrough a pipe 39, and from which pipe a. branch pipe 40 leads .thatconnects with the pipe 38. A pressure regulating valve 41 mayl beprovided in the branch 40 and a gauge 42 may also' be provided in thepipe. When the fluid flows into the cylinder 34 the valve 33 Will'bemoved against the seat 32 and the degree of pressure with which lthevalve 33 is held seated'by the fluid pressure may be controlled in anysuitable manner nd varied by means of the regulating valve Fluid whichis supplied through the pipe 39 is also delivered to the tank orreceiver 27 by means of a branch pipe 43A leading to the tank and inwhich branch pipe is a pressure controlled valve 44 by means of whichbthe pressure may be varied, a gauge y45 and a valve 46, by means ofwhich latter the supply of i'luid to the tank or receiver 27 may be cutoi.

The valve 33 and valve seat 32 are so arranged that the pressure withinthe tank or receiver 27 will tend to seat the valve so that it will notbe unseated by such pressure but is adapted to be unseated by thepressure exerted u on the liquid in the cyl1nder 24 beneath t e piston25. That is when thedie 14 operates upon the work 47 toshape the sameand depress the pad 19, the valve 33 will be maintained seated until thepressure upon the liquid in the cylinder 24 ex-.-

ceeds the pressure in the cylinder 34 which holds the valve 33 seated.When the pressure in the cylinder 34 is overcome the valve- 33 will beunseated and the liquid from the cylinder 24 will How back through thepipe 29 to the receiver 27. f

l The' deliveryl of the liquid from; the rer'eiver 27 into the cylinder24 is controlled by means of another valve 48 which co-operates with avalve seat 49 arranged in a by-pass 50 in the passage 31, and the valve48 is adapted to be actuated ffrom some movable part of the presspreferably by L its other end to alever 54 ulcrumed as at 55, the leverbeing connected .to the stem 56 of the valve 4,8, a yieldable section 57being preferably provided in the rod 52 to prevent injury to the parts.f

Thus during a predetermined time in the cycle of operation of the pressor at the time whenv the ram 13 is approaching the limit of its upwardmovement, the crank 51 will begin to unseat the valve 48 so that by thetime the crank is at the highest point the valve 48 Will be completelyunseated to permit the liquid in the tank orreceiver 27 to be `deliveredunder the influence of the air or Huid pressure upon the liquid, throughthe pipe 29, passage 31, by-pass 50, and the Lower section f the pipe 29to the bottom of the cylinder 24 beneath the piston 25.

While the liquid is thus flowing into the cylinder 24 the valve 33 willbe seated. When the valve 48 is seated the liquid will be trapped in thelower section of the pipe 29 and the bottom of the cylinder 24 and willbedelivered back to the receiver 27, through the passage 31 when thevalve 33 is unSeatedy fupon the liquid in the cylinder 24 by the piston25. y

Wheh the Yliquid is thus trapped 1n the cylinder 24 and when the piston25 is lowpressure pad 19, at

ered by depressing the acts agamst theinstant when the piston 25 thepressure.- of the liquid in the cylinder 24, the piston is suddenlyinterrupted rin its movement which causes a considerable stress orstrain to be exerted upon'the crank IShaft 15 and other parts of themechanism,

if some means is not provided to relieve such a shock.

Therefore to overcome this detrimental and sudden shock, means areprovided Jfor enlarging aI portion of the spacein which the trappedliquid is contained. In the present exemplification of this invention aportion of the passage 31 in the valve containing element 30 is enlargedand this is accomplished by forming or providing an extension 61 whichhas communication with the passage 31. Within this extension 61 isarranged a piston 62 having a pisto`nrod'63 connected with a piston 64that Aoperates in a cylinder 65. The supply pipe 39 for conducting fluidto the cylinder 34 and the tank4 sitioned that it will prevent anyapprecia leaniount of the liquid from entering the extension 61 and thenormal tendency of the yfluid pressure in the cylinder 65 behind thepiston 64 is to hold the piston 62 in such a position.

When, however, the piston acts upon the trapped liquid in the cylinder24 and the lower portion of' the pipe 29 and the adjacent portion of thepassage 31, it willcause some of the trapped liquid to flow under aconsiderable pressure into the extension 6l to move the pistons 62 and64 against the fluid pressure in the cylinder 65, thereby overcomingsuch pressure and permitting the space within which the trapped liquidis confined, to be temporarily and slightly enlarged, .with the resultthat the sudden shock or stress upon the crank shaftl and other portionsof the press will be overcome.

As soon as the pressure upon the liquid in the cylinder 24 is increasedsuiliciently to overcome the pressure exerted upon the valve 33, the.latter will be unseated and the liquid will flow back to the tank orreceiver 27. As soon as the pressure of the iiuid upon the pistons 64and 62 is greater than the pressure upon the liquid, the pistons 64 and,62 will be moved from the position shown in Figure 3, back to theposition shown in Figure 1. -1

Ports or passages 68 and 69 may be provided respectively in theycylinders 65 and extension 61 to permitl the escape of air and therebynot interfere with the operation of the pistons 62 and 64.

If desired a control valve 70 may be provided at any convenient point inthe pipe 39 or extension 66.

By means of the control valves 41 and 67 the respective pressures in thecylinders 34 and 65 may be varied at will.

While the preferred form of the inventon has been herein shown anddescribed, it is to be understood that various changes may be made inthe details of construction and in the combination and arrangement ofthe several parts, within the scope of the claims, without departingfrom the spirit of this invention.

What is claimed as new is 1. In combination, a pressure pad, hydraulicmeans for resistingthe movement of the pad in one direction, said means,em-

' bodying a liquid and a piston element per-Y able upon the liquid `andmeans operating automatically at the time the piston starts to moveagainst the stress of the liquid, to eliminate the shock to theactuating mechanism which would be caused by the sudden resistance ofthe liquid to the movement of the piston.

2. In combination, a pressure pad, hydraulic means for resisting themovement of the pad in one direction, said means embodying a liquid anda piston-element operable upon the liquid, variable resistance means forcontrolling the resistance pressure exerted by the piston upon theliquid,

and means operating automatically at the time the piston starts to moveagainst the stress of the liquid, to eliminate the shock to theactuating mechanism which would be caused by the sudden resistance ofthe liquid to the movement of the piston.

3. In combination, a pressure pad, hy-

draulic means for resisting the movement of the pad in one direction,said smeans eniborlying a liquid and a piston .element operable upon theliquid, and fluid controlled means operable automatically at the timethe piston starts to move against the stress of Vthe liquid, toeliminate the shock to the actuating mechanism which would be caused bythe sudden resistance of the liquid to the 'movement of the piston.

4. In combination, a pressure pad, hydraulic means for resisting themovement of the pad in one direction, said means embodyingv a liquid anda piston element operable upon the liquid, variable resistance means forcontrolling the resistance pressure exerted by the piston upon theliquid, and fluid controlled means operable automatically at the timethe piston starts to move against theA vstress of the liquid, toeliminate theshock tothe actuatin mechanism which would be caused by t esudden resistance of the liquid to the movement of the piston. f

5. In combination, a `pressure pad, hydraulic means for resisting themovement of the pad in one direction, said means embodying a liquid anda iston element operable upon the liquid, uid pressure controlled meansautomatically operable at a predetermined time in the cycle of operationof the said pad to eliminate the shock to the movement of the pad whichwould be caused by the sudden resistance of the liquid to the movementof said piston, and lmeans :for varying at will the said uid pressure.

6. In combination, a pressure pad, hydraulic means for resisting themovement of the padin one direction, said means embodying anon-compressible liquid and a piston element operable upon the l1qu1d,

the cyc e of operation of thesaid pad to eliminate the shock to themovement of the pad which would be caused by the sudden resistance oftheliquid to the movement o said piston, and means Jfor varying at Will thesaid fluid pressure.

7. In combination, a pressure pad, hydraulic means for resisting themovement of the pad in one direction, said means embodying a container'for the liquid and a piston operable upon the liquid, and means operableautomatically to increase'the liquid containing area in the saidcontainer, ata predetermined time in the cycle of operation of thepiston, to overcome the shock which would be caused by the suddenresistance of the liquid in said container to the movement ot' thepiston.

8. In combination, a pressure pad, hydraulic means for resisting themovement of the pad in one direction, said -means embodying avcontainer'for the liquid and a piston operable upon the liquid, andfluid pressure controlled means operable automatically to increase theliquid containing bodying piston,

area in the said container, at a predetermined time in the cycle ofoperation of the to overcome the shock which would be caused by thesudden resistance of the yliquid in said container to the movement ofthe piston.

9. 'In combination, a pressure pad, hy-

rdraulic means for resisting the movement of the pad in one direction,said means ema container for the liquid and a piston operable upon theliquid, fluid pressure controlled means operable automati- -cally toincrease the liquid'eontaining area inl vthe said container, at apredetermined time in the cycle of operation of. the piston, to overcomethe shock 'which would be caused by the sudden resistance of the liquidin said container to the' movement of the piston, and means for varyingat will the said fluid pressure.

10. In combination', a pressure pad, hydraulic means for resisting themovement of the ad in one direction, said means embodying a containerfor the liquid anda piston operable upon the liquid, and means operableautomatically to increase the liquid containing area in the saidvcontainer, at a predetermined time inthe'cycle of operation of thepiston, to overcome the shock which would be caused by the suddenresistance ofthe liquid in said container to the movement of the piston,the last said means. also operating automatically at a predeterminedtime in the cycle of operation of the piston'to restore 'the saidcontainer to the normal liquid containing area.

11. In combination, a pressure pad, hydraulic means for resisting themovement of the pad in one direction, said means embodying a liquid anda piston element operable u on the liquid, and means operating toeliminate the shock to the actuatingA mechanism which would be caused bythe sudden resistance of the liquid to the movement of the piston.

12. In combinatiom a pressure pad, hydraulie means for resisting themovement o the pad in one direction, said means embodying a liquid and apiston element operable upon the liquid, and means operating at the timethe piston -starts to move against thestress of the liquld, to eliminatethe shock to the actuating mechanism which would be caused by the suddenresistance of the liquid to the movement of the piston.

In testimony whereof I have signed my name to this specification, onthis 29th day of March, A. D. 1928.

FREDRIor-I J. RODE.

